Header

UZH-Logo

Maintenance Infos

TTL proteins scaffold brassinosteroid signaling components at the plasma membrane to optimize signal transduction in Arabidopsis


Amorim-Silva, Vitor; Garcia-Moreno, Alvaro; Castillo, Araceli G; Lakhssassi, Naoufal; Esteban Del Valle, Alicia; Perez-Sancho, Jessica; Li, Yansha; Pose, David; Perez-Rodriguez, Josefa; Lin, Jinxing; Valpuesta, Victoriano; Borsani, Omar; Zipfel, Cyril; Macho, Alberto P; Botella, Miguel A (2019). TTL proteins scaffold brassinosteroid signaling components at the plasma membrane to optimize signal transduction in Arabidopsis. Plant Cell, 31(8):1807-1828.

Abstract

Brassinosteroids (BRs) form a group of steroidal hormones essential for plant growth, development and stress responses. BRs are perceived extracellularly by plasma membrane receptor-like kinases, which activates an interconnected signal transduction cascade, leading to the transcriptional regulation of BR-responsive genes. TETRATRICOPEPTIDE THIOREDOXIN-LIKE (TTL) genes are specific for land plants and their encoded proteins are defined by the presence of protein-protein interaction motives, i.e. an intrinsic disordered region at the N-terminus, six tetraticopeptide repeat domains and a C-terminus with homology to thioredoxins, thus likely mediating the assembly of multiprotein complexes. Phenotypic, molecular and genetic analyses show that TTL proteins are positive regulators of BR signaling in Arabidopsis. TTL3 directly interacts with a constitutively active BRI1 receptor kinase, BSU1 phosphatase and the BZR1 transcription factor and associates with BSK1, BIN2 kinases but not with BAK1. A functional TTL3-GFP shows dual cytoplasmic-plasma membrane localization. Depleting the endogenous BR content reduces plasma membrane localization of TTL3-GFP, while increasing BR content causes its plasma membrane relocalization, where it strengthens the association of BR signaling components. Our results reveal that TTL proteins promote BR responses and suggest that may function as scaffold proteins by bringing together cytoplasmic and plasma membrane BR signaling components.

Abstract

Brassinosteroids (BRs) form a group of steroidal hormones essential for plant growth, development and stress responses. BRs are perceived extracellularly by plasma membrane receptor-like kinases, which activates an interconnected signal transduction cascade, leading to the transcriptional regulation of BR-responsive genes. TETRATRICOPEPTIDE THIOREDOXIN-LIKE (TTL) genes are specific for land plants and their encoded proteins are defined by the presence of protein-protein interaction motives, i.e. an intrinsic disordered region at the N-terminus, six tetraticopeptide repeat domains and a C-terminus with homology to thioredoxins, thus likely mediating the assembly of multiprotein complexes. Phenotypic, molecular and genetic analyses show that TTL proteins are positive regulators of BR signaling in Arabidopsis. TTL3 directly interacts with a constitutively active BRI1 receptor kinase, BSU1 phosphatase and the BZR1 transcription factor and associates with BSK1, BIN2 kinases but not with BAK1. A functional TTL3-GFP shows dual cytoplasmic-plasma membrane localization. Depleting the endogenous BR content reduces plasma membrane localization of TTL3-GFP, while increasing BR content causes its plasma membrane relocalization, where it strengthens the association of BR signaling components. Our results reveal that TTL proteins promote BR responses and suggest that may function as scaffold proteins by bringing together cytoplasmic and plasma membrane BR signaling components.

Statistics

Citations

Dimensions.ai Metrics
1 citation in Web of Science®
1 citation in Scopus®
Google Scholar™

Altmetrics

Downloads

2 downloads since deposited on 25 Jun 2019
2 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Plant and Microbial Biology
07 Faculty of Science > Zurich-Basel Plant Science Center
Dewey Decimal Classification:580 Plants (Botany)
Language:English
Date:1 August 2019
Deposited On:25 Jun 2019 12:19
Last Modified:25 Sep 2019 00:36
Publisher:American Society of Plant Biologists
ISSN:1040-4651
OA Status:Closed
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1105/tpc.19.00150
PubMed ID:31189737

Download

Closed Access: Download allowed only for UZH members